Major safety boost for reefers

With the development of a cable coiler that can work at heights of over nine metres, Hans Følsgaard A/S has solved a recognised safety problem for a large shipping and freight company in the handling of refrigerated containers.

In the refrigerated cargo logistics industry, safe power supply and cable management has been a challenge for many years – both on ships and ashore at terminals. Often, there have not been enough power sockets, so several refrigerated containers have to be connected to the same socket. And when up to four containers are stacked on top of each other, a long cable is needed to reach the nearest power source.


Using cable pickers, it is possible to reach the cable from the top container, pick it up and let gravity take care of the rest. But then, when the container has to be moved again, the cable has to be coiled up, and suddenly it is a long way up to the cable tray on the container. Usually the cable is coiled 'as best as possible', but this is far from optimal.


Cables are a potential safety hazard

The work is time-consuming, impractical and also a safety hazard. When containers are stacked high, the ship's crew can only coil the bottom metres of each cable. This means that a cable can hang in the air while the container is being moved. The staff at the terminal then have to rewind the rest of the cable and often this is not done well enough.


A freely swinging cable can cause injuries to the crew or it can get stuck, complicating unloading and leading to dangerous situations. If the cable gets stuck, it will eventually be cut, but this presents a host of other challenges. If cables often get stuck and are cut, new cables must be installed, which costs time, money and labour.


This is where Hans Følsgaard comes in

Hans Følsgaard was asked by a large shipping company to provide a technical solution to the problem and several options were discussed. Technical Manager Lei Zhang was part of the team, and says that one of the first ideas for solving the cable problem was to look at how a vacuum cleaner rolls in its cord after use:


"It seemed like an obvious idea to have a device in the cable tray of each refrigerated container that could roll the cable in – just like a regular vacuum cleaner. However, the idea was rejected as the containers on deck are exposed to extremely harsh and changing conditions that would soon jeopardise reliability," he explains.


It was also tested whether it was possible to coil up the cable from the bottom, but this was made impossible by transverse rods for lashing. Finally, it was decided to develop a device to coil up the cable that can reach up to the top refrigerated containers in the stack. The prototype of this cable coiler was ready in 2019.


Interrupted by the Pandemic

The prototype of the Følsgaard cable coiler consisted of a telescopic pole that could be extended to a total length of 9.5 metres to reach refrigerated containers on the 'fourth floor'. At the top was a sensor-controlled motor that activates two wheels to rewind the cable. These two wheels slide apart and release the cable once it is up in the cable tray.


Technical Manager Lei Zhang: "On 11 July 2019, we were able to test the prototype under realistic conditions and the test went well. There were things that needed to be adjusted, but we were optimistic. The concept proved its worth. We left knowing that we had found the right solution. And then everything came to a standstill."


The pandemic hit and everything shut down. Partners, subcontractors, component suppliers ... The delay was frustrating, but work continued behind the scenes and important decisions were made on the design and choice of materials.


"We decided that the telescopic pole should be made of carbon fibre, as it becomes long and difficult to operate when fully extended and used in challenging conditions. For the same reason, the battery was placed at the bottom to ensure stability. The speed was adjusted so that the winding process did not take too long and the battery capacity was increased to three hours," Lei Zhang explains.


Closer to the start of production

After further testing, optimisation of the electronics in the unit and material selection, the innovative cable coiler has moved closer to actual production.


The number of units to be produced cannot yet be quantified, nor is there an exact delivery date for the first units. Initially, selected key harbours will be identified, where different vessels can be equipped with a cable coiler. Secondly, an obvious target group would be the terminals, some of which currently use lifts to reach the top cable trays of refrigerated containers.


There are obvious benefits for all parties in terms of time savings, reduced repair costs, fewer damaged goods in containers and smoother, uninterrupted unloading. But first and foremost, the developers behind the invention are pleased to have found a solution to eliminate a risk factor for crews on ships and in harbours around the world.

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